Jan 16, 2009

Tech - US, Chinese researchers engineer invisible cloak: study

WASHINGTON (AFP) – In a breakthrough that could signal a new era for human technology, US and Chinese researchers announced they are a step closer to creating an invisibility shield.

In a development made possible by advances in designing complex mathematical commands known as algorithms, engineers at Duke University, North Carolina were able to create what they call "metamaterials."

These materials can "guide electromagnetic waves around an object, only to have them emerge on the other side as if they had passed through an empty volume of space," according to the team, whose work was published in the January 16 edition of the journal Science.

The cloaking phenomenon is similar to mirages seen at a distance on a hot day, according to senior researcher David R. Smith.

"You see what looks like water hovering over the road, but it is in reality a reflection from the sky," Smith said.

"In that example, the mirage you see is cloaking the road below. In effect, we are creating an engineered mirage with this latest cloak design."

The team, who were backed by the US Air Force Office of Scientific Research and the National Science Foundation of China among others, worked off their 2006 prototype that proved the project's feasibility.

But Smith said their latest cloak is far superior to the original design, Smith said.

"The new device can cloak a much wider spectrum of waves -- nearly limitless -- and will scale far more easily to infrared and visible light," he said.

"The approach we used should help us expand and improve our abilities to cloak different types of waves."

The breakthrough has the potential of advancing numerous technologies that already exist, and ideas that have yet to be devised.

"By eliminating the effects of obstructions, cloaking devices could improve wireless communications, or acoustic cloaks could serve as protective shields, preventing the penetration of vibrations, sound or seismic waves," said the team.

The cloak, measuring 20 inches (50.8 centimeters) by four inches (10 centimeters) and less than an inch (2.5 centimeter) high, is constructed with 10,000 fiberglass pieces arranged in parallel rows, 6,000 of which are unique.

The unique algorithms that can affect electromagnetic waves determined the shape and placement of each piece, the team indicated.